/**
 * Data can often be a complicated mix of numbers and letters (file names
 * are a common example) and sorting them in a natural manner is quite a
 * difficult problem.
 *
 * Fortunately a deal of work has already been done in this area by other
 * authors - the following plug-in uses the [naturalSort() function by Jim
 * Palmer](http://www.overset.com/2008/09/01/javascript-natural-sort-algorithm-with-unicode-support) to provide natural sorting in DataTables.
 *
 *  @name Natural sorting
 *  @summary Sort data with a mix of numbers and letters _naturally_.
 *  @author [Jim Palmer](http://www.overset.com/2008/09/01/javascript-natural-sort-algorithm-with-unicode-support)
 *
 *  @example
 *    $('#example').dataTable( {
 *       columnDefs: [
 *         { type: 'natural', targets: 0 }
 *       ]
 *    } );
 */

(function () {

    /*
     * Natural Sort algorithm for Javascript - Version 0.7 - Released under MIT license
     * Author: Jim Palmer (based on chunking idea from Dave Koelle)
     * Contributors: Mike Grier (mgrier.com), Clint Priest, Kyle Adams, guillermo
     * See: http://js-naturalsort.googlecode.com/svn/trunk/naturalSort.js
     */
    function naturalSort(a, b) {
        var re = /(^-?[0-9]+(\.?[0-9]*)[df]?e?[0-9]?$|^0x[0-9a-f]+$|[0-9]+)/gi,
            sre = /(^[ ]*|[ ]*$)/g,
            dre = /(^([\w ]+,?[\w ]+)?[\w ]+,?[\w ]+\d+:\d+(:\d+)?[\w ]?|^\d{1,4}[\/\-]\d{1,4}[\/\-]\d{1,4}|^\w+, \w+ \d+, \d{4})/,
            hre = /^0x[0-9a-f]+$/i,
            ore = /^0/,
        // convert all to strings and trim()
            x = a.toString().replace(sre, '') || '',
            y = b.toString().replace(sre, '') || '',
        // chunk/tokenize
            xN = x.replace(re, '\0$1\0').replace(/\0$/, '').replace(/^\0/, '').split('\0'),
            yN = y.replace(re, '\0$1\0').replace(/\0$/, '').replace(/^\0/, '').split('\0'),
        // numeric, hex or date detection
            xD = parseInt(x.match(hre), 10) || (xN.length !== 1 && x.match(dre) && Date.parse(x)),
            yD = parseInt(y.match(hre), 10) || xD && y.match(dre) && Date.parse(y) || null;

        // first try and sort Hex codes or Dates
        if (yD) {
            if (xD < yD) {
                return -1;
            }
            else if (xD > yD) {
                return 1;
            }
        }

        // natural sorting through split numeric strings and default strings
        for (var cLoc = 0, numS = Math.max(xN.length, yN.length); cLoc < numS; cLoc++) {
            // find floats not starting with '0', string or 0 if not defined (Clint Priest)
            var oFxNcL = !(xN[cLoc] || '').match(ore) && parseFloat(xN[cLoc], 10) || xN[cLoc] || 0;
            var oFyNcL = !(yN[cLoc] || '').match(ore) && parseFloat(yN[cLoc], 10) || yN[cLoc] || 0;
            // handle numeric vs string comparison - number < string - (Kyle Adams)
            if (isNaN(oFxNcL) !== isNaN(oFyNcL)) {
                return (isNaN(oFxNcL)) ? 1 : -1;
            }
            // rely on string comparison if different types - i.e. '02' < 2 != '02' < '2'
            else if (typeof oFxNcL !== typeof oFyNcL) {
                oFxNcL += '';
                oFyNcL += '';
            }
            if (oFxNcL < oFyNcL) {
                return -1;
            }
            if (oFxNcL > oFyNcL) {
                return 1;
            }
        }
        return 0;
    }

    jQuery.extend(jQuery.fn.dataTableExt.oSort, {
        "natural-asc": function (a, b) {
            return naturalSort(a, b);
        },

        "natural-desc": function (a, b) {
            return naturalSort(a, b) * -1;
        }
    });

}());
